There was a time when I thought I was (糟糕的) English speaker in the world. So I can understand your feelings.
In fact, you don't need to worry too much. There are (十亿) of people speaking English in the world, but not all of them are really good at it. Just be (勇敢的) when talking.
Second, try some new ways (提升) your English. You'll be more confident if you are better at it. You can try speaking English aloud when you're alone, reading some English (小说) or listening to English songs.
Third, dream big and start small. Begin by having some (轻松的) and short conversations with friends. Then, talk to (某人) you don't know very well. For example, an English friend on the Internet.
Finally, don't speak too fast. It's easy to make mistakes when talking too fast. So, you can slow down to give yourself (足够的) time to think of the right words.
I hope next time, you (接受) your mistakes when speaking English and learn from them. Follow my (建议). I'm sure you'll become a better English speaker!